I would not be surprised if Aaron Lawson is an injustice collector.
Lot of mass killers are injustice collectors like Elliot Rodger, Eric Harris, Adam Lanza, Seung-Hui Cho, and Stephen Paddock.
Injustice Collectors
http://www.psybersquare.com/family/family_injustice.html
Characteristics of Injustice Collectors:
1.) Injustice Collectors are convinced that they are never wrong. How is it possible that they are never wrong? It is simple: They are always right.
2.) Injustice Collectors never apologize. Ever. For anything.
3.) Injustice Collectors truly believe that they are morally and ethically superior to others and that others chronically do not hold themselves to the same high standards as the injustice collector does.
4.) Injustice Collectors make the rules, break the rules and enforce the rules of the family. They are a combined legislator, police, and judge and jury of
5.) Injustice Collectors never worry about what is wrong with themselves as their "bad list" grows. Their focus is always on the failings of others.
6.) Injustice Collectors are never upset by the disparity of their rules for others with their own expectations of themselves.
7.) Injustice Collectors rationalize their own behavior with great ease and comfort.
Here are more with 20 characteristics
http://www.lisaescott.com/forum/2009/11/25/are-they-injustice-collector
Characteristics of Injustice Collectors
1. Injustice collectors are never wrong. How is it possible that they are never wrong? It's simple: They are always right.
2. Injustice collectors never apologize. Ever. For anything.
3. Injustice collectors truly believe they are morally and ethically superior to others and that others seem incapable of holding themselves to the same high standards as the injustice collector does.
4. Injustice collectors make the rules, break the rules and enforce the rules of the family. They are a combination of legislator, police, judge and jury to those they consider their subjects. They forever banish from their kingdom any subject they deem disloyal, and only grant clemency if there is sufficient (in their eyes) contrition.
5. Injustice collectors never worry about what is wrong with them as their "bad" list grows. Their focus is always on the failings of others.
6. Injustice collectors are never troubled by the disparity between their rules for others and their own expectations of themselves. Injustice collectors rationalize their own behavior with great ease and comfort.
7. Injustice collectors have an external orientation; the problem always exists in the world, outside of themselves, and in their view, the world would be an acceptable place if their rules and standards were followed at all times.
8. Injustice collectors do not have a capacity for remorse, empathy or guilt.
9. Injustice collectors scoff at the idea of therapy, therapists, self-help books, and other tools used by people who struggle to live with them.
10. The phrase "walking on eggshells" describes life with an injustice collector.
11. The IC (injustice Collector) will prey upon your weaknesses to frame all issues in their terms.
12. IC's will always cry foul when you are 'mean' to them and accuse you of being nasty when you are confronting them with their negative behavior.
13. They are titanically insecure and cannot trust anyone. All relationships they have, even with their own parents and children and trustless and must be reinforced by subordination over and over.
14. They can only strengthen relationships through imprisoning their mates and banning behaviors and other relationships. Friends and family are a huge threat to the IC.
15. They must repetitively revisit situations where you service them, give in to them and agree with them. They will over time shrink your world to a small plot of empty activities that only they like. They are terrified of travel, meeting new people, understanding new concepts and paroling you from any punishment they have previously 'convicted' you of.
16. They do not care about you at all, they care about aggrandizing themselves with you as an assistant producer.
17. They will occasionally do something for you, but if you are not completely brainwashed, it will be a negative experience for you in the end. Example is throwing you a birthday party. I guarantee you will not have fun at your own party.
18. They will force you to choose between them and other things you like or love. The more you choose them, the more they will make you choose them over and over. They do not understand the concept of loyalty at all.
19. Hypocrisy is their modus operandi for debating and arguing with you. Everything they say about you is true about them. (aka Projection) It makes it so you try to 'win' fights by getting them to agree with you, which they never can because their whole position is false.
20. Your life will disappear into their lives. Your hopes and dreams will fade, even in your own mind. You will eat what they want, you will watch what they want on TV, you will vacation where they want, or not at all.
Looking at injustice collector characteristics, it is narcissism, which it is at heart. Injustice collector is another term for extreme narcissism. Envy often occurs with narcissism.
Connection between narcissism and envy explained
https://www.sciencedaily.com/releases/2013/02/130212172025.htm
The Narcissist and Jealousy
http://thenarcissisticlife.com/the-narcissist-and-jealousy/